Wind and solar power can provide important new sources of electricity that are renewable and do not contribute to greenhouse gas generation. However, these sources provide the electricity in a highly variable manner. This makes it difficult to match the electricity production to the needs of the electrical utilities that consume it. In addition, the electrical transmission system capability will need to be increased in order to move the electricity from where it is generated to where it is consumed. A further issue is that electricity does not provide a means to make a substantial reduction in petroleum use in the near term since it cannot be used to directly replace petroleum use in present cars and trucks. A major switch to plug in hybrids and electric vehicles would be required.
Various forms of storage of renewable electricity have been proposed to deal with the variability of production. They include pumped water and compressed air. However, these approaches have substantial cost and scale issues, and are limited in location. Another approach that has been suggested is to use the electricity to manufacture hydrogen as discussed below. None of these approaches provide easily substituted fuels for petroleum based transportation fuels.
There is a substantial literature on concepts for the use of electricity from renewable sources for the generation of hydrogen including [M. Hsu, Renewable Energy operated Hydrogen Reforming System, International Patent WO 2004/071947; Levene, J. I., M. K. Mann, R. Margolis, and A. Milbrandt, An Analysis of Hydrogen Production from Renewable Electricity Sources, National Renewable Energy Laboratory, Presented at ISES 2005 Solar World Congress, Orlando, Fla., Aug. 6-12, 2005, NREL/CP-560-37612 (2005); Bartholomy, O., Renewable Hydrogen From Wind In California, Proceedings, National Hydrogen Association, March 2005.
Some of these processes are electrolysis based. However, the purpose of these concepts is for a hydrogen-based economy. There are problems with distribution, storage, use of hydrogen that in most cases are not acknowledged by the authors, and the common usage of electrolysis releases the oxygen generated in the process rather than utilizing it in a beneficial way.
Use of renewable electricity to produce liquid fuels for transportation can provide a means to both address the issue of the variability from wind and solar energy and also convert it into an energy form which has greatest near term impact for reducing use of petroleum. The problem of the highly variable nature of electricity generation can be more easily addressed when the electricity is used in this manufacturing application rather than when it has to be matched to the needs of the electrical grid.
Plasma technology offers a way for using electricity for conversion of natural gas and other hydrocarbon fuels into synthesis gas (syngas). Synthesis gas can then be used to make a variety of fuels. Conventional thermal plasmas have been used. [CORMIER, J. M., RUSU I., Syngas production via methane steam reforming with oxygen: plasma reactors versus chemical reactors: The future of technological plasmas, Journal of physics. D, Applied physics vol. 34, no18, pp. 2798-2803 (2001); see also Chun, Y. N., Kim, S. C., Production of hydrogen-rich gas from methane by thermal plasma reform, Journal of the Air and Waste Management Association, v 57, n 12, December, 2007, p 1447-1451]. Also, nonthermal plasma have been used [Nozaki, T., Tsukijihara, H., Fukui, W., Okazaki, K., Kinetic analysis of the catalyst and nonthermal plasma hybrid reaction for methane steam reforming, Energy and Fuels, v 21, n 5, September/October, 2007, p 2525-2530; also, Ouni, F., Khacef, A. Cormier, J. M., Effect of oxygen on methane steam reforming in a sliding discharge reactor, Chemical Engineering and Technology, v 29, n 5, May, 2006, p 604-609]. Microwave discharges have also been suggested [Jasinski, M., Dors, M., Mizeraczyk, J., Production of hydrogen via methane reforming using atmospheric pressure microwave plasma, Journal of Power Sources, v 181, n 1, Jun. 15, 2008, p 41-45] The present invention overcomes these drawbacks of these approaches.